Radio-frequency interference suppressing choke with elongated portions for brush-type motors

ABSTRACT

A choke  10,  for suppressing radio-frequency interference of a brush-type motor, includes a single wire having a portion  15  wound about a coil axis A to define a plurality of coils  14  including two outermost coils  16  and  18.  An attaching structure  20  extends from each outermost coil and is disposed generally transverse with respect to the coil axis. Each attaching structure is constructed and arranged to be inserted through an associated opening in a supporting structure and to be bent so as secure the choke to the supporting structure. An elongated end portion  22  extends from each attaching structure so as to be spaced from and generally parallel to the coil axis. The elongated end portions extend in opposite directions. One of the elongated end portions is constructed and arranged to be directly electrically connected to an electrical connector of a motor and the other of the elongated end portions is constructed and arranged to be in electrical connection with a brush of the motor.

This is a divisional of application Ser. No. 09/822,304, filed Mar. 28,2001, which is hereby incorporated by reference.

This application is based on U.S. Provisional Application No.60/227,175, filed Aug. 23, 2000 and claims the benefit thereof forpriority purposes.

FIELD OF THE INVENTION

This invention relates to d.c. electric motors for automotiveapplications and, more particularly, to a choke having features forimproved mechanical and electrical connection with components of a brushcard assembly.

BACKGROUND OF THE INVENTION

Typical multi-pole automotive d.c. electric motors use bus bars toconduct current between the electrical connector of the motor andassociated components such as chokes, capacitors, and brushes.Conventional bus bars have to be manufactured and physically attached,supported and connected with the motor. Typically, the bus bars areriveted to the brush card of the motor. The electrical connection isusually achieved using soldered or heat-fused joints.

Thus, there is a need to reduce the number of electrical connectionsrequired on the motor's brush card, to eliminate costly bus bars and toreduce the number of separate mechanical fasteners needed on the brushcard.

Furthermore, conventionally, wound wire coils or chokes are installedclose to the brushes of d.c. motors, particularly in automotiveapplications. The purpose of the chokes is to suppress radio-frequencyinterference (RFI) generated by the motor. Generally, the chokes arephysically attached to the brush card of the motor using fixing orfastening techniques that require additional specific parts orprocesses, for example, the ends of the chokes may be soldered toconductors that are riveted to the brush card, the chokes may beinstalled within purpose-designed locations molded into the brush card,and/or clips or other fasteners may be used to attached the chokes.

Hence, there is also a need to provide secure mechanical attachment ofthe choke to the brush card while avoiding the necessity of either amolded brush card or specific fastening components.

SUMMARY OF THE INVENTION

An object of the present invention is to fulfill the needs referred toabove. In accordance with the principles of the present invention, thisobjective is obtained by providing a choke for suppressingradio-frequency interference of a brush-type motor. The choke includes asingle wire having a portion wound about a coil axis to define aplurality of coils including two outermost coils. An attaching structureextends from each outermost coil and is disposed generally transversewith respect to the coil axis. Each attaching structure is constructedand arranged to be inserted through an associated opening in asupporting structure and to be bent so as secure the choke to thesupporting structure. An elongated end portion extends from eachattaching structure so as to be spaced from and generally parallel tothe coil axis. The elongated end portions extend in opposite directions.One of the elongated end portions is constructed and arranged to bedirectly electrically connected to an electrical connector of a motorand the other of the elongated end portions is constructed and arrangedto be in electrical connection with a brush of the motor.

In accordance with another aspect of the invention, a brush cardassembly for a d.c. motor includes at least one choke having a portionwound about a coil axis to define a plurality of coils including twooutermost coils, an attaching structure extending from each outermostcoil and being generally transverse with respect to the coil axis. Anelongated end portion extends from each attaching structure so as to bespaced from and generally parallel to the coil axis, the elongated endportions extending in opposite directions. The assembly further includesa brush card having first and second opposing sides and a pair ofopenings through the opposing sides. Each attaching structure isdisposed through an associated opening and bent so as to be adjacent tothe second side, with the wound portion of the choke being disposed onthe first side of the brush card, such that the choke is secured to thebrush card. A brush is mounted on the brush card and is in electricalconnection with one of the elongated end portions. An electricalconnector is mounted on the brush card. The electrical connector has aterminal receiving the other elongated end portion of the choke.

In accordance with yet another aspect of the invention, a method ofconnecting a choke to a brush card assembly is provided. The chokeinclude a portion wound about a coil axis to define a plurality of coilsincluding two outermost coils. An attaching structure extends from eachoutermost coil and is disposed generally transverse with respect to thecoil axis. An elongated end portion extends from each attachingstructure so as to be spaced from and generally parallel to the coilaxis. The elongated end portions extend in opposite directions. Thebrush card assembly includes a brush card having first and secondopposing sides and a pair of openings through the opposing sides. Abrush and an electrical connector are mounted on the brush card. Theelectrical connector has a terminal. The method includes the steps ofinserting each attaching structure through an associated opening, withthe wound portion of the choke being disposed on the first side of thebrush card, bending each attaching structure so as to be adjacent to thesecond side, thereby securing the choke to the brush card, directlyelectrically connecting one of the elongated end portions with theterminal, and electrically connecting the other elongated end portionwith the brush.

Other objects, features and characteristics of the present invention, aswell as the methods of operation and the functions of the relatedelements of the structure, the combination of parts and economics ofmanufacture will become more apparent upon consideration of thefollowing detailed description and appended claims with reference to theaccompanying drawings, all of which form a part of this specification.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a choke for a d.c motor provided inaccordance with the principles of the invention;

FIG. 2 is a right end view of the choke of FIG. 1;

FIG. 3 is view of a front of a brush card assembly of the inventionshowing a pair of chokes mounted to a brush card and connected toterminals of a motor connector; and

FIG. 4 is a view of the back of brush card assembly of the inventionshowing chokes crimped to secure the chokes to the brush card.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a choke, generally indicated 10, for suppressingradio-frequency interference of a brush-type, multi-pole d.c. motor, isshown in accordance with the principles of the invention. The choke 10comprises a single conductive wire 12 having a portion 15 wound about acoil axis A to define a plurality of coils 14 including two outermostcoils, 16 and 18. The choke 10 includes an attaching structure,generally indicated at 20 and 20′, extending from each of outermostcoils 16 and 18, generally transverse with respect to the coil axis A.An elongated end portion 22 extends from each attaching structure 20 and20′ so as to be spaced from and generally parallel to the coil axis A.The elongated end portions 22 extend in opposite directions from theattaching structures 20 and 20′ a distance substantially equal to alength of the portion 15 wound about the axis A. A center axis B and Cof each elongated end portion 22 is disposed on a common plane P.

In the illustrated embodiment, attaching structure 20 includes a firstportion 24 bent to extend transversely from an associated elongated endportion 22 and generally along the plane P. A second portion 26 is bentto extend downwardly and transversely with respect to the first portion24. A third portion 28 is bent to extend from the second portion 26 soas to be generally parallel with the first portion 24, but below planeP. A fourth portion 30 bent to extend upwardly from the third portion 28to the outermost coil 16. The fourth portion 30 is generally parallelwith respect to the second portion 26.

As best shown in FIG. 2, attaching structure 20′ includes a firstportion 27 bent to extend downwardly and transversely with respect tothe elongated end portion 22″. A second portion 29 is bent to extendtransversely from the first portion 27 below plane P. A third portion 31bent to extend upwardly from the second portion 29 to the outermost coil18. The third portion 31 is generally parallel with respect to the firstportion 27.

FIGS. 3 and 4 show the connection of chokes 10 of FIGS. 1 and 2 to abrush card assembly, generally indicated at 32. The brush card assembly32 includes a brush card 34 having a first side 36 and an opposingsecond side 38. An electrical connector 40 and brushes 42 are mounted tothe brush card 34. The brush card 34 includes two pairs of openings 43therethrough. One pair of openings 43 is associated with one choke 10for mounting the choke to the brush card 34. Each opening 43 is sized toreceive an associated attaching structure 20 or 20″ of the choke 10.Thus, during assembly each attaching structure 20 and 20′ is disposedthrough an associated opening 43 with the wound portion 15 of the choke10 being disposed on the first side 36 of the brush card 34. Theattaching structures 20 and 20′ are bent generally 90 degrees about axisD (which, as shown in FIG. 1, is parallel to the coil axis A) so as toengage, or at least be adjacent to, the second side 38 of the brush card34 thus securing the choke 10 with respect to the brush card 34. In theillustrated embodiment, the attaching structures 20 and 20′ are bentoutwardly or away from each other, but it can be appreciated that theattaching structures 20 and 20′ can be bent toward each other to achievethe same securing function.

The use of the attaching structures 20 and 20′ avoids the need forseparate choke fastening components or a molded brush card, provides asimple attachment of the chokes, and reduces the need forenvironmentally-sensitive solder pastes or adhesives.

As best shown in FIG. 3, since the end portions 22 are elongated, one ofthe end portions 22′ is coupled to a terminal 44 of the connector 40. Inparticular, the terminal 44 defines an open channel 48 which receives atleast a portion of the end portion 22′. The other end portion 22″ iselectrically coupled to a brush shunt wire 46.

The use of elongated end portions 22 of the choke 10 reduces the numberof electrical connections required on the brush card, eliminates thecostly manufactured bus bars, and reduces the number of separatemechanical fasteners need on the brush card.

The foregoing preferred embodiments have been shown and described forthe purposes of illustrating the structural and functional principles ofthe present invention, as well as illustrating the methods of employingthe preferred embodiments and are subject to change without departingfrom such principles. Therefore, this invention includes allmodifications encompassed within the spirit of the following claims.

What is claimed is:
 1. A choke for suppressing radio-frequencyinterference of a brush-type motor, the choke comprising: a single wirehaving a portion wound about a coil axis to define a plurality of coilsincluding two outermost coils, an attaching structure extending fromeach outermost coil and being generally transverse with respect to thecoil axis, each attaching structure being constructed and arranged to beinserted through an associated opening in a supporting structure and tobe bent so as secure the choke to the supporting structure, and anelongated end portion extending from each attaching structure so as tobe spaced from and generally parallel to the coil axis, the elongatedend portions extending in opposite directions, one of the elongated endportions being constructed and arranged to be directly electricallyconnected to an electrical connector of a motor and the other of theelongated end portions being constructed and arranged to be inelectrical connection with a brush of the motor.
 2. The choke of claim1, wherein a center axis of each elongated end portions is disposed on acommon plane.
 3. The choke of claim 2, wherein at least one of theattaching structures includes a first portion extending transverselyfrom an associated elongated end portion and generally along the commonplane, a second position extending downwardly and transversely withrespect to the first portion, a third portion extending from the secondportion so as to be generally parallel with the first portion, and afourth portion extending upwardly from the third portion to anassociated outermost coil, the fourth portion being generally parallelwith respect to the second portion.
 4. The choke of claim 2, wherein atleast one of the attaching structures includes a first portion extendingdownwardly and transversely with respect to an associated elongated endportion, a second portion extend transversely from the first portion anda third portion extending upwardly from the second portion to anassociated outermost coil, the third portion being generally parallelwith respect to the first portion.
 5. The choke of claim 2, wherein theelongated end portions are disposed in spaced relation.
 6. The choke ofclaim 1, wherein each elongated end portion extends from an attachingstructure a distance substantially equal to a length of the portionwound about the axis.
 7. A method of connecting a choke to a brush cardassembly, the choke including a portion wound about a coil axis todefine a plurality of coils including two outermost coils, an attachingstructure extending from each outermost coil and being generallytransverse with respect to the coil axis, and an elongated end portionextending from each attaching structure so as to be spaced from andgenerally parallel to the coil axis, the elongated end portionsextending in opposite directions, the brush card assembly including abrush card having first and second opposing sides and a pair of openingsthrough the opposing sides, a brush mounted on the brush card, and anelectrical connector mounted on the brush card, the electrical connectorhaving a terminal, the method including the steps of: inserting eachattaching structure through and associated opening, with the woundportion of the choke being disposed on the first side of the brush card,bending each attaching structure so as to be adjacent to the secondside, thereby securing the choke to the brush card, directlyelectrically connecting one of the elongated end portions with theterminal, and electrically connecting the other elongated end portionwith the brush.
 8. The method of claim 7, wherein the terminal includesan opened channel and the method includes receiving at least a portionof said one elongated end portion in the opened channel.